Weird vending machines?

So, as I entered a random shop, I came across weird blocks. I don't know what are these. I first thought it was a bug, so I relogged. But nothing changed after that, so I guess these are normal vending machines... But I'm still confused o-o

Place 1 Food Cart 3 down, then 2 vends on top of it. Because the food cart's top is phantomed the vends stack on it without being 3 tall. This hides most of the vend but still makes the vend accessible.